That's true. But under a fee-for-service (FFS) model, providers get paid per procedure they do. That gives them an incentive to order more testing, and generally "do more stuff."
There's also an IT angle (relevant for HN!): medical systems don't always talk to each other. Which means that maybe the patient got an MRI last month, in a different health system... but I don't have access to it in my health system, so I order a redundant one.
